From Drucker in The Effective Executive:
The knowledge worker cannot be supervised closely or in detail. He can only be helped. But he must direct himself, and he must direct himself toward performance and contribution, that is, toward effectiveness.
The motivation of the knowledge worker depends on his being effective, on his being able to achieve. If effectiveness is lacking in his or her work, his commitment to work and to contribution will soon wither, and he will become a time-server going through the motions from 9-5.